In recent years, there have been transmitters that use multi-dimensional rotated constellations (e.g., rotated quadrature amplitude modulation (QAM) constellations) (see Patent Literature 1 and Non-Patent Literature 1, for example).
Such a transmitter has a function of multiplying each of vectors by an orthogonal matrix (rotating each of vectors), each of the vectors having, as elements thereof, a predetermined number of real-valued pulse amplitude modulation (PAM) symbols output from a symbol mapper. In such a transmitter, the predetermined number of elements of each vector resulting from the rotation process (i.e., each rotated vector) are spread along the time axis.